When you say you can't see them, are you referring to when you are trying to add them to a page or when looking at yoursite.com/dashboard/extend/install/ ?

EDIT: You won't see those add-ons in the Block Types list, if that was what you are referring to.

EDIT 2: Make sure the add-on has been installed correctly by going to yoursite.com/dashboard/extend/install/. If it shows up as installed, try a reinstall.

Thanks for your quick reply. The problem is when I try to add them to a page, they don't appear. I went to /extend/install/ and saw all my add-ons listed, so then I tried to uninstall the media library to reinstall it and got this error:
"Fatal error: Call to a member function deleteBlock() on a non-object in /home2/jasonch2/public_html/kwbc/concrete/models/block_types.php on line 691"

I feel as if it keeps getting worse haha.

You should post a support ticket with the developer of Media Library here:
https://www.concrete5.org/marketplace/addons/media-library/support/...

Thanks, I will. One of the main reasons why I'm confused is because NONE of my add-ons show up when I try and add them to a page.

When you go to your dashboard > extend concrete5, so you see them all listed as currently installed?

Has your server experienced any abrupt shutdowns?
Try refreshing your database schema.

I'm having the same problem with another add-on, the Studio Testimonials. It's everywhere except the block type list, and I get the same error when trying to uninstall. Is there a way to reinstall manually?

Also having this issue with the free galleria addon. Is there a solution for this? Thanks.